I thought I would pass this on.
I have had a couple questions on whether it was possible to modify an InstallShield project during a nightly build. You bet you can. I have at least two clients who are doing this.
InstallShield projects can be saved in Binary or XML format (you set this in the General Information view). Just set your project type to XML and have your nightly build modify the project.
Please make a backup copy of your project before you start working with this.